Alloy

ABSTRACT

THIS INVENTION RELATES TO AN ALLOY CAPABLE OF BEING POLISHED TO A MIRRORLIKE FINISH. THE ALLOY IS VERY HARD HAVING A HARDNESS OF UP TO 1200 ON THE VICKERS SCALE AND COMPRISES A NICKEL BASE WITH HIGH BORON CONTENT, UP TO NINE PRECENT BY WEIGHT, WITH CHROMIUM.

United States Patent 3,578,441 ALLOY Otto Knotek, Lausanne, Switzerland, assignor to Eutectic Corporation, Flushing, N.Y. No Drawing. Filed Nov. 4, 1968, Ser. No. 773,285 Int. Cl. C220 19/02 [1.8. '0]. 75-171 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an alloy capable of being polished to a mirrorlike finish. The alloy is very hard having a hardness of up to 1200 on the Vickers scale and comprises a nickel base with high boron content, up to nine percent by weight, with chromium.

There has been a need in the art for an alloy that would provide a tough, wear resistant hard surface that could be polished to bright mirrorlike finish, to take the place of some of the plated alloys (such as chrome plating) which cannot maintain their high finish during hard service.

The general object of the present invention is to provide an alloy that can be polished to an extremely high smooth and lustrous finish.

The alloy of the present invention comprises the alloying of elemental nickel with chromium and boron. It was found that with high boron additions, up to nine percent by weight, a boron, chrome, nickel trinary alloy can be formed with a high incidence of nickel borides and chrome borides. This alloy having a high degree of nickel borides and chrome borides is very hard, up to 1200 on the Vickers scale and the boride integration permit a highly lustrous mirrorlike finish. This alloy, it has been found, has remarkably reduced voids.

The alloy of the present invention has the following alloy composition in the Weight percentages indicated:

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Element: Weight percent Boron 6 to 9 Chromium 3.3 to 7.3 Nickel Balance essentially 2. The alloy of claim 1 wherein said alloy composition is of the following composition in the indicated weight percentages Element: Weight percent Boron 6.7 to 8.3 Chromium 4.3 to 6.5 Nickel Balance essentially 3. The alloy of claim 2 that can be polished to a lustrous finish.

4. The alloy of claim 3 with a hardness of up to 1200 on the Vickers scale.

References Cited UNITED STATES PATENTS 2/1959 Tour -l7l 5/1960 Shepard 75l71 RICHARD O. DEAN, Primary Examiner 

